It could be a infection in throat.Normally it occurs in viral infections that after sore throat
one develops loss of voice.
It could be viral as you had headache, fever
You must consult an ENT specialist
and get your throat examined.
you might have vocal cord palsy/ or due to infection and inflammation you are not able to speak then the vocal cords will be normal.
So without hearing your voice and without examining it is difficult to comment.
Get well soon.